Riotous fight
I believe the answer is:
melee
'riotous fight' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for melee that I've seen before include "Scrap" , "Confused fight or scuffle" , "Confused brawl" , "A confused free-for-all" , "A confused fight or muddle" .)